U.S. patent number 10,111,381 [Application Number 15/624,116] was granted by the patent office on 2018-10-30 for walk power mower with transmission providing both forward and reverse propulsion.
This patent grant is currently assigned to THE TORO COMPANY. The grantee listed for this patent is THE TORO COMPANY. Invention is credited to Todd A. Porter, Chadwick A. Shaffer.
United States Patent |
10,111,381 |
Shaffer , et al. |
October 30, 2018 |
**Please see images for:
( Certificate of Correction ) ** |
Walk power mower with transmission providing both forward and
reverse propulsion
Abstract
A walk power mower having a cutting deck supported upon the
ground by a front and rear wheel(s). The mower includes a traction
drive system incorporating a bidirectional transmission adapted to
propel the mower alternatively in both forward and reverse
directions. In some embodiments, the mower may include a single
bidirectional transmission (e.g., powering only rear wheel(s) or
only front wheel(s) of the mower), while in other embodiments, two
bidirectional transmissions may be provided to power both the front
and the rear wheel(s). In other embodiments, the mower may include
a bidirectional transmission powering the rear wheel(s), while the
front wheel(s) may be attached to the deck via a caster
assembly.
Inventors: |
Shaffer; Chadwick A. (Oakdale,
MN), Porter; Todd A. (Rosemount, MN) |
Applicant: |
Name |
City |
State |
Country |
Type |
THE TORO COMPANY |
Bloomington |
MN |
US |
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Assignee: |
THE TORO COMPANY (Bloomington,
MN)
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Family
ID: |
64691172 |
Appl.
No.: |
15/624,116 |
Filed: |
June 15, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170367259 A1 |
Dec 28, 2017 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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15472415 |
Mar 29, 2017 |
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15195648 |
Jun 28, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B62B
5/0073 (20130101); B62D 51/04 (20130101); A01D
34/69 (20130101); B62B 5/0026 (20130101); A01D
34/6806 (20130101); A01D 34/824 (20130101); A01D
2101/00 (20130101); A01D 2034/6843 (20130101); A01D
2034/6837 (20130101); A01D 34/76 (20130101); A01D
2034/6825 (20130101) |
Current International
Class: |
B62D
51/04 (20060101); B62B 5/00 (20060101); A01D
34/69 (20060101); A01D 34/68 (20060101); A01D
34/82 (20060101); A01D 34/76 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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101361428 |
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Nov 2009 |
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CN |
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2 170 032 |
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Apr 2012 |
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EP |
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62-18323 |
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Jan 1987 |
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JP |
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04-166475 |
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Jun 1992 |
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JP |
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2007-053991 |
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Mar 2007 |
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JP |
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WO 2013-122563 |
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Aug 2013 |
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WO |
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Other References
US. Appl. No. 15/195,648, filed Jun. 28, 2016, Wadzinski. cited by
applicant .
U.S. Appl. No. 15/472,415, filed Mar. 29, 2017, Shaffer et al.
cited by applicant .
U.S. Appl. No. 15/195,648: Office Action dated Oct. 30, 2017; 11
pages. cited by applicant .
AS Motor Germany, "Four wheel driven mower, Model AS 53 B6 RB-Kat"
Operating Instructions. From Serial No. 020910020001. Issued Feb.
24, 2011, V7.0; 32 pages. cited by applicant .
Husqvarna, Lawn Mower "HU725AWDHQ" Operator's Manual. Nov. 16,
2015; 40 pages. cited by applicant .
MTD Products, "Self Propelled Mower" Operator's Manual. All Wheel
Drive Model Series K and L. Form No. 769-11812A. Nov. 16, 2016; 28
pages. cited by applicant.
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Primary Examiner: Winner; Tony H
Assistant Examiner: Arce; Marlon A
Attorney, Agent or Firm: Mueting, Raasch & Gebhardt,
P.A.
Parent Case Text
This application is a continuation-in-part of U.S. patent
application Ser. No. 15/472,415, filed Mar. 29, 2017, which is a
continuation-in-part of U.S. patent application Ser. No.
15/195,648, filed Jun. 28, 2016, both of which are incorporated
herein by reference in their respective entireties.
Claims
What is claimed is:
1. A walk power equipment unit comprising: a housing supported upon
the ground by at least a front wheel and a rear wheel, the housing
adapted to traverse the ground in both a forward direction and an
opposite, reverse direction; a handle comprising a handle member
extending upwardly and rearwardly from the housing, wherein the
handle member includes: an upper end; and a lower end, the lower
end attached to the housing; a prime mover carried by the housing;
and a variable speed traction drive system carried by the housing,
the traction drive system comprising: a bidirectional transmission
operatively connected to a drive wheel selected from the group
comprising the front wheel and the rear wheel, the transmission
operable to selectively rotate the drive wheel to propel the
housing over the ground; and a control system comprising a handle
grip translatable along the handle member, wherein the handle grip
activates the transmission to power the drive wheel for movement of
the housing in the forward direction when the handle grip is
translated downwardly along the handle member from a neutral
position, and wherein the handle grip activates the transmission to
power the drive wheel for movement of the housing in the reverse
direction when the handle grip is translated upwardly along the
handle member from the neutral position.
2. The power equipment unit of claim 1, wherein the prime mover is
connected to the transmission to provide power to the same.
3. The power equipment unit of claim 1, further comprising an
independent propulsion motor connected to the transmission to
provide power to the same.
4. The power equipment unit of claim 1, wherein the transmission
comprises one or more electric motors.
5. The power equipment unit of claim 1, wherein the housing
comprises a mower cutting deck that supports a rotating cutting
member operatively connected to the prime mover.
6. The power equipment unit of claim 1, wherein the front wheel is
connected to a caster assembly, the caster assembly mounted to the
housing such that the caster assembly pivots, relative to the
housing, about a vertical caster axis.
7. The power equipment unit of claim 1, further comprising one or
more cables connecting the handle grip to the transmission.
8. The power equipment unit of claim 1, wherein the power equipment
unit includes two rear wheels configured as drive wheels, and
wherein the transmission is connected to both of the rear wheels
via a differential.
9. A walk power mower comprising: a deck supported upon the ground
by front wheels and rear wheels, the deck adapted to traverse the
ground in both a forward direction and an opposite, reverse
direction, wherein the front wheels and/or the rear wheels operate
as powered drive wheels of the mower; a handle comprising a handle
member extending upwardly and rearwardly from the deck, wherein the
handle member includes: an upper end; and a lower end, the lower
end attached to the deck; a prime mover carried by the deck, the
prime mover operatively connected to a cutting member associated
with the deck; and a variable speed, bidirectional transmission
carried by the deck, wherein the transmission selectively rotates
at least one of the drive wheels to effect propulsion of the deck
over the ground; and a control system comprising a handle grip
positioned at or near the upper end of, and translatable along, the
handle member, wherein translation of the handle grip activates the
transmission to power at least one of the drive wheels for movement
of the deck: in the forward direction when the handle grip is
translated downwardly along the handle member from a neutral
position; and in the reverse direction when the handle grip is
translated upwardly along the handle member from the neutral
position.
10. The mower of claim 9, wherein each front wheel forms part of a
front wheel assembly that further comprises a caster arm, the
caster arm rotationally connected to the deck so that each front
wheel assembly, and thus its associated front wheel, rotates about
a vertical caster axis relative to the deck.
11. The mower of claim 9, wherein the transmission is connected to
both of the rear wheels.
12. The mower of claim 11, wherein the prime mover is connected to
the transmission to provide power to the same.
13. The mower of claim 11, further comprising an independent
propulsion motor connected to the transmission to provide power to
the same.
14. The mower of claim 11, wherein the transmission comprises an
electric motor.
15. The mower of claim 11, further comprising a second transmission
connected to both of the front wheels, wherein the handle grip
activates the second transmission for movement of the deck in the
forward direction when the handle grip is translated downwardly
along the handle member.
16. A walk power mower comprising: a deck supported upon the ground
by front wheels and rear wheels, the deck adapted to traverse the
ground in both a forward direction and an opposite, reverse
direction, wherein one or more of the front wheels and the rear
wheels operate as a powered drive wheel of the mower; a handle
comprising a handle member extending upwardly and rearwardly from
the deck, wherein the handle member includes: an upper end
comprising a grip area; and a lower end attached to the deck; a
prime mover carried by the deck, the prime mover operatively
connected to a cutting member associated with the deck; a variable
speed, bidirectional traction drive system carried by the deck,
wherein the traction drive system selectively rotates the drive
wheel to effect propulsion of the deck over the ground; and a
control system carried on the handle and operatively connected to
the traction drive system, wherein the control system comprises a
first control member and a second control member that are each
independently movable between a neutral position corresponding to a
neutral mode of the traction drive system, and an engaged position
corresponding to a powered mode of the traction drive system,
wherein: the first control member, when moved from the neutral
position to the engaged position, is adapted to manipulate the
traction drive system from: the neutral mode; to a forward powered
mode wherein the traction drive system rotates the drive wheel in a
first direction corresponding to the forward direction of the deck;
and the second control member, when moved from the neutral position
to the engaged position, is adapted to manipulate the traction
drive system from: the neutral mode; to a reverse powered mode
wherein the traction drive system rotates the drive wheel in a
second direction corresponding to the reverse direction of the
deck.
17. The mower or claim 16, wherein the traction drive system
comprises a transmission connected to the drive wheel.
18. The mower of claim 17, wherein the prime mover is connected to
the transmission to provide power to the same.
19. The mower of claim 17, further comprising an independent
propulsion motor connected to the transmission to provide power to
the same.
20. The mower of claim 17, wherein the transmission comprises an
electric motor.
21. The mower of claim 16, wherein the first and second control
members comprise first and second bails, respectively, that are
each pivotally attached to the handle.
22. The mower of claim 16, wherein the powered drive wheel
comprises one or more of the rear wheels.
23. The mower of claim 22, wherein the traction drive system
comprises: a rear transmission adapted to provide power to the rear
wheels, and a front transmission adapted to provide power to the
front wheels, wherein the front transmission is adapted to: provide
power to the front wheels for travel of the deck in the forward
direction when the rear transmission provides power to the rear
wheels for travel of the deck in the forward direction; and
terminate power to the front wheels when the rear transmission is
engaged for travel in the reverse direction.
Description
TECHNICAL FIELD
Embodiments of the present disclosure relate to a walk power mower
for cutting grass and, more particularly, to a transmission
providing both forward and reverse propulsion.
BACKGROUND
Walk power mowers are well known for cutting grass. For example,
such mowers are commonly used by property owners, such as
homeowners, to cut their lawns. Such mowers have a cutting deck
that houses a rotary grass cutting blade. The deck is supported by
a plurality of wheels for rolling over the ground. A handle extends
upwardly and rearwardly from the deck. A user who walks on the
ground behind the deck grips a handle grip of the handle to
manipulate and guide the mower during a grass mowing operation.
It can be difficult or is undesirable for some users to manually
push a walk power mower over the ground in order to cut one's lawn.
It is tiring to do so, particularly when the area being mowed is
either large, hilly, or both. Thus, many mowers have traction drive
systems that utilize part of the power generated by the prime mover
carried on the mower to drive at least one pair of the mower's
wheels, either the front wheels or the rear wheels, in a forward
direction. Such a self-propelled mower relieves the user of the
necessity of having to bodily push the mower over the ground. This
greatly eases the physical effort required from the user in mowing
one's lawn. The user now primarily guides or steers the mower
during the powered forward motion provided by the traction drive
system and the prime mover.
There are times when mowing one's lawn when the user needs to pull
the mower in reverse at least over short distances. For example,
when a user cuts grass under the branches of a bush, the user will
ordinarily drive the mower forwardly so that the cutting blade
reaches under the branches sufficiently to cut whatever patch of
grass lies beneath the branches. However, once this patch of grass
is cut, the user must pull back on the handle to pull the mower out
from under the branches of the bush. While the traction drive
system is designed with a one-way clutch to allow the drive wheels
to free-wheel during reverse motion so that the user is not pulling
back against the resistance provided by the gearing in the traction
drive system, the drive wheels of the mower are typically unpowered
during this reverse motion.
As a result, many users end up having to manhandle or wrestle the
mower back in this reverse motion scenario. This requires the user
to expend physical energy and for some users accomplishing manual
reverse motion of the mower may be difficult or impossible in some
situations. This difficulty is exacerbated for those users in which
trimming operations requiring reverse motions of the mower are
numerous or are required on difficult terrain. For example, in
trimming beneath a bush, pulling back on the mower is even more
difficult if the user has to pull the mower back up a slope to get
it out from under the branches of the bush.
Another problem sometimes present during reverse mower movement is
unintentional lifting of the mower's front wheels. That is, when a
pulling force is applied at the offset mower handle, a moment is
produced that causes the mower to rotate about a line of contact
between the ground and the rear wheels. As one can appreciate, this
rotation may cause the mower's front wheels to lift. While such
lifting of the front wheels may be beneficial for various mower
operations (e.g., turning), maintaining front wheel engagement with
the ground during reverse may be advantageous (e.g., to maintain
quality of cut).
SUMMARY
On aspect of this disclosure relates to a walk power equipment unit
having a housing supported upon the ground by at least a front
wheel and a rear wheel, the housing adapted to traverse the ground
in both a forward direction and an opposite, reverse direction. The
power equipment unit further includes a handle having a handle
member extending upwardly and rearwardly from the housing, wherein
the handle member includes: an upper end; and a lower end, the
lower end attached to the housing. A prime mover is carried by the
housing, as is a variable speed traction drive system. The traction
drive system includes: a bidirectional transmission operatively
connected to a drive wheel selected from the group comprising the
front wheel and the rear wheel, the transmission operable to
selectively rotate the drive wheel to propel the housing over the
ground; and a control system comprising a handle grip translatable
along the handle member. The handle grip activates the transmission
to power the drive wheel for movement of the housing in the forward
direction when the handle grip is translated downwardly along the
handle member from a neutral position, and the handle grip
activates the transmission to power the drive wheel for movement of
the housing in the reverse direction when the handle grip is
translated upwardly along the handle member from the neutral
position.
In another aspect of the present disclosure, a walk power mower is
provided that includes a deck supported upon the ground by front
wheels and rear wheels, the deck adapted to traverse the ground in
both a forward direction and an opposite, reverse direction,
wherein the front wheels and/or the rear wheels operate as powered
drive wheels of the mower. The mower also includes a handle
comprising a handle member extending upwardly and rearwardly from
the deck, wherein the handle member includes: an upper end; and a
lower end, the lower end attached to the deck. A prime mover is
carried by the deck and operatively connected to a cutting member
associated with the deck. A variable speed, bidirectional
transmission is also carried by the deck, wherein the transmission
selectively rotates at least one of the drive wheels to effect
propulsion of the deck over the ground. A control system is
provided and includes a handle grip positioned at or near the upper
end of, and translatable along, the handle member. Translation of
the handle grip activates the transmission to power at least one of
the drive wheels for movement of the deck: in the forward direction
when the handle grip is translated downwardly along the handle
member from a neutral position; and in the reverse direction when
the handle grip is translated upwardly along the handle member from
the neutral position.
In still yet another aspect of the present disclosure, a walk power
mower is provided that includes a deck supported upon the ground by
front wheels and rear wheels, the deck adapted to traverse the
ground in both a forward direction and an opposite, reverse
direction, wherein one or more of the front wheels and the rear
wheels operate as a powered drive wheel of the mower. The mower
also includes a handle having a handle member extending upwardly
and rearwardly from the deck, wherein the handle member has: an
upper end comprising a grip area; and a lower end attached to the
deck. A prime mover is also provided and carried by the deck, the
prime mover being operatively connected to a cutting member. A
variable speed, bidirectional traction drive system is also carried
by the deck, wherein the traction drive system selectively rotates
the drive wheel to effect propulsion of the deck over the ground. A
control system is carried on the handle and operatively connected
to the traction drive system, wherein the control system comprises
a first control member and a second control member that are each
independently movable between a neutral position corresponding to a
neutral mode of the traction drive system, and a fully engaged
position corresponding to a powered mode of the traction drive
system. The first control member, when moved from the neutral
position to the engaged position, is adapted to manipulate the
traction drive system from: the neutral mode; to a forward powered
mode wherein the traction drive system rotates the drive wheel in a
first direction corresponding to the forward direction of the deck.
Similarly, the second control member, when moved from the neutral
position to the engaged position, is adapted to manipulate the
traction drive system from: the neutral mode; to a reverse powered
mode wherein the traction drive system rotates the drive wheel in a
second direction corresponding to the reverse direction of the
deck.
In yet another aspect, the present disclosure relates to a walk
power mower including: a grass cutting deck surrounding a grass
cutting member, wherein the cutting deck is adapted to travel over
the ground in both a forward direction and a reverse direction; and
a handle comprising an upwardly and rearwardly extending handle
member. The handle member includes an upper end comprising a grip
area, and a lower end pivotally attached to the cutting deck such
that the handle member pivots about a transverse pivot axis within
an operating range of pivotal motion defined by: an upper stop
corresponding to the handle being in a first operating orientation;
and a lower stop corresponding to the handle being in a second
operating orientation, the operating range of pivotal motion being
at least about 5 degrees. A resilient member is operatively
positioned between the lower stop and the handle member, wherein
the resilient member is adapted to bias the handle member to a
location at or near the upper stop.
In still another aspect, the present disclosure relates to a walk
power mower comprising: a grass cutting deck supported upon the
ground by a front wheel and a rear wheel, the cutting deck
surrounding a grass cutting member, wherein the cutting deck is
adapted to traverse the ground in both a forward direction and a
reverse direction; at least one transmission adapted to selectively
provide driving power to at least one wheel of the front and rear
wheels; and a handle comprising first and second laterally
spaced-apart and parallel handle members each extending upwardly
and rearwardly from the cutting deck. The first and second handle
members each comprise: an upper end; and a lower end pivotally
attached to the cutting deck such that the handle members pivot
about a transverse pivot axis within an operating range of pivotal
motion defined by: an upper stop corresponding to the handle being
in a first operating orientation; and a lower stop corresponding to
the handle being in a second operating orientation, the operating
range of pivotal motion being about 5-20 degrees. A control member
is carried at or near the upper ends of the first and second handle
members, wherein the control member, when moved to a first engaged
position, is adapted to place the transmission into operation so
that the transmission propels the mower in the forward direction.
First and second resilient members are provided and positioned
between the deck and the first and second handle members,
respectively, the first and second resilient members adapted to
bias the first and second handle members to a location at or near
the upper stop.
In still yet another aspect, a walk power mower is provided that
includes: a grass cutting deck supported upon the ground by a pair
of front wheels and a pair of rear wheels, the cutting deck
surrounding at least one grass cutting blade; and a variable speed
traction drive system carried on the cutting deck and adapted to
selectively provide driving power to at least one wheel of the
front and rear pairs of wheels to propel the mower over the ground
in both a forward direction and a reverse direction. A handle is
also provided and includes first and second laterally spaced-apart
and parallel handle members extending upwardly and rearwardly from
the cutting deck, wherein the first and second handle members each
comprise: an upper end; and a lower end pivotally attached to a
rear portion of the cutting deck such that the handle members pivot
about a transverse pivot axis within an operating range of pivotal
motion defined by an upper stop and a lower stop. The mower also
includes a control system carried at or near the upper ends of the
first and second handle members, the control system operable to
engage the traction drive system to selectively propel the cutting
deck in both the forward direction and the reverse direction. First
and second resilient members are provided and positioned between
the deck and the first and second handle members, respectively. The
first and second resilient members are adapted to resiliently
deform when the handle members pivot, about the transverse pivot
axis, from a position at or near the upper stop toward a position
at or near the lower stop.
Yet another aspect of this disclosure relates to a walk power mower
which comprises a deck supported by a pair of front wheels and a
pair of rear wheels. The deck has at least one grass cutting blade
that rotates in a substantially horizontal plane about a
substantially vertical axis to cut grass. The deck also has an
upwardly and rearwardly extending handle that is gripped by a user
who walks on the ground behind the deck to guide and manipulate the
deck during motion of the deck over the ground. A prime mover is
carried by the deck, the prime mover being operably coupled to the
blade for effecting powered rotation of the blade. A variable speed
traction drive system is carried on the deck, the prime mover being
operably coupled to the traction drive system for effecting powered
rotation of the front wheels and the rear wheels. The traction
drive system comprises a rear transmission having a rear axle that
is operatively connected to the rear wheels for powering the rear
wheels to provide self-propelled motion of the deck in a first
direction of motion over the ground, a front transmission having a
front axle that is operatively connected to the front wheels for
powering the front wheels to provide self-propelled motion of the
deck in a second direction of motion over the ground that is
opposite to the first direction of motion, and a control system
carried on the handle that is selectively operable by a user for
placing only one transmission at a time into operation so that the
rear transmission is active to propel the deck in the first
direction while the front transmission is inactive or the front
transmission is active to propel the deck in the second direction
while the rear transmission is inactive.
Yet another aspect of this disclosure relates to a walk power mower
which comprises a traction drive system on a grass cutting deck
having a pair of front wheels and a pair of rear wheels. A pair of
transmissions power at least one pair of wheels on the deck. A
first one of the transmissions provides forward motion of the mower
when it is active and a second one of the transmissions provides
rearward motion of the mower when it is active. A slidable handle
grip is provided on a handle extending upwardly and rearwardly from
the cutting deck. The handle grip has a cross bar long enough to be
gripped by both hands of the user. The handle grip activates the
first one of the transmissions when it is slid downwardly on a
handle out of a neutral position thereof as a user walks forwardly
holding the cross bar of the handle grip. The handle grip activates
the second one of the transmissions when it is slid upwardly on the
handle out of the neutral position as a user walks rearwardly
holding the cross bar of the handle grip.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of this disclosure will be described more fully in the
following Detailed Description, when taken in conjunction with the
following drawings, in which like reference numerals refer to like
elements throughout.
FIG. 1 is a perspective view of one embodiment of a walk power
mower according to this disclosure;
FIG. 2 is an enlarged perspective view of a portion of the handle
of the mower of FIG. 1, particularly illustrating the return to
neutral system that causes the slidable handle grip of the handle
to return to a neutral position in which the traction drive system
is disengaged once the user releases the handle grip;
FIG. 3 is a perspective view of the underside of the cutting deck
of the mower of FIG. 1, particularly illustrating a dual
transmission traction drive system;
FIG. 4 is a perspective view of a portion of a second embodiment of
a walk power mower according to this disclosure;
FIG. 5 is an enlarged perspective view of a portion of the handle
of the mower of FIG. 4, particularly illustrating a second
embodiment of the return to neutral system that causes the slidable
handle grip of the handle to return to a neutral position in which
the traction drive system is disengaged once the user releases the
handle grip;
FIG. 6 is a perspective view of the underside of a mower cutting
deck in accordance with another embodiment of this disclosure, the
mower shown with a bidirectional, single (forward and reverse)
transmission traction drive system;
FIGS. 7A-7C illustrate various embodiments of a traction drive
system in accordance with embodiments of the present disclosure,
wherein: FIG. 7A is a diagrammatic view of a bidirectional
transmission powered by a belt connected to a prime mover of the
mower; FIG. 7B is a diagrammatic view of a bidirectional
transmission powered by an independent motor separate from the
mower's prime mover; and FIG. 7C is a diagrammatic view of a
bidirectional transmission(s) attached to a drive wheel of the
mower, wherein each transmission is configured as an electric
motor;
FIG. 8 is a perspective view of a portion of an exemplary handle
for use with the mower of FIG. 6, the handle including a forward
bail and a separate reverse bail;
FIG. 9 is a perspective view of a mower in accordance with another
embodiment of the present disclosure, the mower including castering
front wheels;
FIGS. 10A-10B illustrate a mower in accordance with another
embodiment of this disclosure, the mower incorporating a biased or
"floating" handle, wherein: FIG. 10A is a rear perspective view;
and FIG. 10B is a front perspective view;
FIG. 11 is an enlarged view of a portion of the mower of FIGS.
10A-10B;
FIG. 12 is an exploded perspective view of a portion of the mower
of FIGS. 10A-10B;
FIG. 13 is a perspective view of a resilient member for use with
the mower of FIGS. 10A-10B; and
FIG. 14 is a side elevation view of the mower of FIGS. 10A-10B.
The figures are rendered primarily for clarity and, as a result,
are not necessarily drawn to scale. Moreover, various
structure/components, including but not limited to fasteners,
electrical components (wiring, cables, etc.), and the like, may be
shown diagrammatically or removed from some or all of the views to
better illustrate aspects of the depicted embodiments, or where
inclusion of such structure/components is not necessary to an
understanding of the various exemplary embodiments described
herein. The lack of illustration/description of such
structure/components in a particular figure is, however, not to be
interpreted as limiting the scope of the various embodiments in any
way. Still further, "Figure x" and "FIG. x" may be used
interchangeably herein to refer to the figure numbered "x."
DETAILED DESCRIPTION
One embodiment of a walk power mower 2 according to this disclosure
is illustrated in FIG. 1. Mower 2 comprises a housing or cutting
deck 4 that is formed with a generally toroidal cutting chamber 6
that faces downwardly and is open at its bottom. Deck 4 is
supported for rolling over the ground by a pair of front wheels 8
and a pair of rear wheels 10. A prime mover 12, such as an internal
combustion engine, is carried on top of deck 4. Referring now to
FIG. 3, the drive shaft 14 of the prime mover extends vertically
downwardly with its lower end extending into cutting chamber 6. A
horizontal cutting member or blade 16 is positioned within cutting
chamber 6 and is removably secured to the lower end of drive shaft
14 to rotate in a generally horizontal cutting plane to cut
grass.
Referring again to FIG. 1, mower 2 is a three-in-one mower having
side discharge, rear bagging and mulching modes of operation. In
the side discharge mode, a side discharge chute 18 can be mated
with a side discharge opening to discharge grass clippings to the
side of mower 2 when a side discharge door 20 is opened. In the
rear bagging mode, a grass clipping collection bag 22 is mated with
a rear discharge opening to collect grass clippings being
discharged to the rear of mower 2 when a rear discharge door 24 is
opened. While FIG. 1 illustrates deck 4 as being both in the side
discharge mode and the rear bagging mode, this is only for the
purpose of illustration as these two modes would not be used
simultaneously. When side discharge chute 18 is removed and side
discharge door 20 is closed and when bag 22 is removed and rear
discharge door 24 is closed, mower 2 is placed into its mulching
mode in which grass clippings are driven downwardly out of cutting
chamber 6 to discharge the clippings beneath mower 2. However,
mower 2 need not have multiple modes of operation, but could be
built as a single purpose side discharge, rear bagger, or mulching
mower.
An upwardly and rearwardly extending handle 26 comprising a pair of
laterally spaced handle members or tubes 28 joined by a top cross
member 30. The lower ends of handle tubes 28 are attached to the
rear of deck 4. Handle 26 includes a U-shaped handle grip 32 that
has a pair of laterally spaced legs 34 connected together by an
upper cross bar 36. Legs 34 of handle grip 32 are telescopically
received on handle tubes 28 of handle 26 for sliding movement
relative thereto. Thus, handle grip 32 is able to slide downwardly
(translate along) on handle tubes 28 as a user walks forwardly
while gripping cross bar 36 of handle grip 32 with both of the
user's hands.
Handle grip 32 slides downwardly by an amount that depends upon how
fast the user walks forwardly. As will be described in more detail
hereafter, the extent or amount of downward travel of handle grip
32 controls a traction drive system 38 (see FIG. 3) of mower 2 to
vary the forward ground speed of mower 2 to correspond to the
user's walking pace. This type of speed controlling, slidable
handle grip is used on the Personal Pace.RTM. line of walk power
mowers manufactured and sold by The Toro Company, the assignee
herein. In addition, this type of slidable handle grip is disclosed
more fully in U.S. Pat. No. 6,082,083 to Stalpes et al., which
patent is hereby incorporated by reference and shall be referred to
as "Stalpes" hereafter.
In Stalpes, handle grip 32 is in a neutral, i.e., a drive
disengaged position, when handle grip 32 is at the top of handle 26
with handle grip 32 located adjacent to cross member 30 that joins
handle tubes 28 together. The only control motion of handle grip 32
in Stalpes is the downward sliding motion that engages the traction
drive system of Stalpes in forward and that varies the forward
ground speed in concert with the user's forward walking pace. When
the user lets go of handle grip 32 in Stalpes, handle grip 32 is
spring biased to slide back up handle 26 to return to the top
thereof at which point the traction drive system becomes disengaged
once again.
In mower 2 of this disclosure, the Stalpes handle grip 32 has been
modified so that the neutral position of handle grip 32 is no
longer at the top of the range of motion of handle grip 32. Now,
the neutral position of handle grip 32 is displaced somewhat
downwardly from cross member 30 of handle 26. A return to neutral
system 40 maintains handle grip 32 in its now lower neutral
position relative to cross member 30 of handle 26.
Handle grip 32 functions as it did in Stalpes when the user grips
cross bar 36 of handle grip 32 and walks forwardly, i.e., handle
grip 32 slides downwardly in the direction of the arrow A in FIG. 1
to activate traction drive system 38 in forward and to vary the
forward ground speed in concert with the user's forward walking
pace. Now, however, if the user grips cross bar 36 of handle grip
32 and walks rearwardly, as when pulling mower 2 back, handle grip
32 is now also able to slide upwardly out of neutral rather than
being held in neutral as in Stalpes. This upward sliding motion of
handle grip 32 is shown by the arrow B in FIG. 1. This activates
traction drive system 38 in reverse and varies the reverse ground
speed of mower 2 in concert with the user's rearward walking pace.
In either forward or reverse powered motion of mower 2, when the
user lets go of handle grip 32, return to neutral system 40 causes
handle grip 32 to slide back to its centered neutral position
between the lower and upper limits of the range of motion of handle
grip 32 to disengage traction drive system 38.
Referring now to FIG. 2, return to neutral system 40 comprises a
rod 42 having an upper end fixed by a bracket 44 to a laterally
extending cross member 46 that is also part of handle grip 32. Rod
42 has spaced upper and lower push nuts 48.sub.u and 48.sub.l fixed
thereto to move with rod 42. Push nuts 48 bear respectively against
one end of cylindrical, upper and lower, push tubes 50.sub.u and
50.sub.l which are spaced along the length of rod 42 and through
which rod 42 slides. Each push tube 50 has an annular thrust
surface 52 that is formed as an integral part thereof. Push tubes
50 are assembled in an inverted relationship relative to each other
along the length of rod 42 such that thrust surface 52 of upper
push tube 50.sub.u is at the lowermost end of upper push tube
50.sub.u while thrust surface 52 of lower push tube 50.sub.l is at
the uppermost end of lower push tube 50.sub.l.
Return to neutral system 40 further includes a U-shaped clevis 54
fixed to handle 26 with the spaced, parallel side walls 56 of
clevis 54 forming an upper wall 56.sub.u and a lower wall 56.sub.l.
Upper and lower push tubes 50.sub.u and 50.sub.l when assembled on
rod 42 are arranged to pass through bores in upper and lower walls
56.sub.u and 56.sub.l of clevis 54 with thrust surfaces 52 on upper
and lower push tubes 50.sub.u and 50.sub.l being inside clevis 54
immediately adjacent to upper and lower walls 56.sub.u and 56.sub.l
of clevis 54. A compression spring 58 is arranged inside clevis 54
with the ends of spring 58 bearing against thrust surfaces 52 of
upper and lower push tubes 50.sub.u and 50.sub.l. When return to
neutral system 40 is properly adjusted and traction drive system 38
is in neutral, spring 58 will force upper and lower push tubes
50.sub.u and 50.sub.l apart until thrust surfaces 52 thereon abut
against the upper and lower walls 56.sub.u and 56.sub.l of clevis
54 and the opposite ends of upper and lower push tubes 50.sub.u and
50.sub.l are immediately adjacent to upper and lower push nuts
48.sub.u and 48.sub.l.
When the user pushes down on handle grip 32 to initiate powered
forward motion of mower 2, upper push nut 48.sub.u on rod 42
presses down on the upper end of upper push tube 50.sub.u to slide
upper push tube 50.sub.u downwardly relative to clevis 54. Note
that lower push tube 50.sub.lremains stationary with rod 42 simply
sliding through lower push tube 50.sub.l since the lower push nut
48.sub.l moves away from the lowermost end of lower push tube
50.sub.l and lower push tube 50.sub.l remains within clevis 54
since thrust surface 52 on lower push tube 50.sub.l is held in
place by its engagement with lower wall 56.sub.l of clevis 54. The
downward motion of upper push tube 50.sub.u compresses spring 58
downwardly. Thus, when the user eventually releases handle grip 32,
the compressed spring 58 pushes back upwardly on upper push tube
50.sub.u to cause the uppermost end of upper push tube 50.sub.u to
push the upper push nut 48.sub.u back upwardly, thereby returning
handle grip 32 to its centered neutral position.
Return to neutral system 40 works the same way but in an opposite
fashion when handle grip 32 is pulled upwardly in the direction of
the arrow B to initiate reverse powered motion of mower 2. This
time it is lower push tube 50.sub.l that is pushed upwardly by
lower push nut 48.sub.l with upper push tube 50.sub.u remaining
stationary. Thus, spring 58 is compressed upwardly. When handle
grip 32 is eventually released, the lowermost end of lower push
tube 50.sub.l pushes downwardly on lower push nut 48.sub.l as the
upward compression of spring 58 is released to slide handle grip 32
back downwardly to return handle grip 32 to its centered neutral
position.
Referring now to FIG. 3, traction drive system 38 comprises a first
rear transmission 60.sub.r which powers rear wheels 10 of mower 2
and a second front transmission 60.sub.fwhich powers front wheels 8
of mower 2. Transmissions 60 preferably comprise, but are not
limited to, mechanical gear drive transmissions that use various
speed reduction stages to reduce the relatively high rotational
speed of drive shaft 14 of prime mover 12 to a lower speed suitable
for self-propelling mower 2 at ground speeds that match the walking
pace of the user. Some of these speed reduction stages are built
into the gearing inside the housings of transmissions 60. However,
the final speed reduction stage is formed by a small diameter drive
gear 62 on each end of an axle 64 of each transmission 60 that
drives a larger diameter driven gear 66 fixedly attached to one of
wheels 8, 10.
Drive gears 62 on the opposite ends of axle 64 of rear transmission
60.sub.r engage the backsides of driven gears 66 of rear wheels 10.
The reverse is true for drive gears 62 for front transmission
60.sub.f which engage the front sides of driven gears 66 of front
wheels 8. Thus, when axles 64 of transmissions 60 are rotated in
opposite directions by the operation of prime mover 12, front and
rear drive wheels 8 and 10 will be rotated in opposite directions
relative to each other. For example, if rear drive wheels 10 are
rotated in a forward direction to propel mower 2 forwardly, front
drive wheels 8 will be rotated in a rearward direction to propel
mower 2 in reverse. As a consequence, it should be apparent that
only one transmission 60 is active at any given time while the
other transmission 60 remains inactive. Either transmission 60 can
be selected to be the one that provides forward motion while the
remaining transmission 60 will then be the one that provides
reverse motion.
Rear transmission 60 preferably has a split axle 64 and provides a
differential action to permit rear wheels 10 to be driven at
different speeds during a turn, such as when the user swings mower
2 around 180.degree. at the end of a pass when mowing his or her
lawn, to avoid tearing or scuffing the grass. Rear wheels 10 may
rotate at different speeds during turns using either an unpowered
or powered differential. For example, in an unpowered differential
which is preferred due to somewhat lower cost, the portion of split
axle 64 powering whichever rear wheel 10 is on the outside of the
turn simply overruns the rotational speed of the portion of split
axle 64 powering the rear wheel 10 on the inside of the turn to
create the difference in wheel speed. Since front wheels 8 of mower
2 are typically lifted up off the ground during such a turnaround
of mower 2, front transmission 60 preferably has a solid axle and
lacks any differential action, thereby reducing overall cost of
mower 2.
Each transmission 60 is provided with a one-way clutch that permits
the wheels driven by that transmission 60 to free wheel when mower
2 is being propelled in a direction opposite to the direction
transmission 60 is designed to operate. In the example where one
transmission is active and is driving mower 2 forwardly while the
other reverse drive transmission is inactive and is not in
operation, the one-way clutch in the inactive reverse drive
transmission permits the drive wheels coupled to that transmission
to rotate freely with respect to the internal gearing of the
reverse drive transmission to avoid the drag or resistance such
internal gearing would otherwise provide when mower 2 moves
forwardly.
Each front and rear transmission 60.sub.f and 60.sub.r is
separately driven by its own independent belt drive 68.sub.f and
68.sub.r from drive shaft 14 of prime mover 12. Each transmission
60 is a rocking transmission of the type disclosed in Stalpes. When
handle grip 32 is in neutral and both transmissions 60 are
inactive, belts 70 in belt drives 68 are sufficiently slack so that
the input pulleys on transmissions 60 are stationary even though
drive shaft 14 of prime mover 12 is rotating. Effectively, mower 2
is at rest even with the engine running when handle grip 32 is not
being pushed or pulled by the user.
However, as the user slides handle grip 32 up or down on handle 26
in either the downward direction A or the upward direction B, this
motion rocks one transmission 60 in a direction (rearwardly about
its axle 64 for rear transmission 60.sub.r and forwardly about its
axle 64 for front transmission 60.sub.f) to tighten drive belt 70
to the rocking transmission while leaving drive belt 70 to other
transmission slack. As drive belt 70 to the rocking transmission
becomes taut, the transmission becomes active to begin rotating the
pair of wheels powered by the rocking transmission. The speed of
rotation of axle 64 of the rocking transmission, and thus the
ground speed of mower 2, progressively increases as handle grip 32
is moved ever further in the selected direction and the tautness of
belt 70 progressively increases. Thus, the ground speed of mower 2
progressively increases from zero to a maximum speed as handle grip
32 travels out of neutral to the end of its range of motion in the
selected direction A or B. This enables the ground speed of mower 2
to be matched to the walking pace of the user whether mower 2 is
being propelled in forward or reverse.
First and second Bowden cables (not shown) having inner wires
carried within outer conduits operably couple handle grip 32 to
transmissions 60. The first Bowden cable has a "live cable" setup
in which a rear end of the outer conduit is fixed or clamped to
handle 26 and the front end of the outer conduit is fixed or
clamped to a lower end of one handle tube 28 or to a rear end of
deck 4. The rear end of the inner wire of the first Bowden cable is
secured to an opening 72 in a pivotal tab 74 (see FIG. 2) that is
rotated rearwardly when handle grip 32 is moved downwardly in the
direction of arrow A. The front end of the inner wire of the first
Bowden cable is then attached to rear transmission 60.sub.r to rock
rear transmission 60.sub.r rearwardly during downward motion of
handle grip 32 in the direction of arrow A. In this "live cable"
setup of the first Bowden cable, the downward motion of handle grip
32 causes the "live" inner wire of the first Bowden cable to slide
rearwardly within the outer conduit in order to rock rear
transmission 60.sub.r rearwardly while the outer conduit remains
fixed in place. The "live cable" setup of the first Bowden cable
and its interaction with pivotal tab 74 is shown and described in
more detail in the Stalpes patent which has previously been
incorporated by reference herein.
The second Bowden cable has a "live conduit" setup in which the
front end of the inner wire is fixed or clamped in place to deck 4
and the rear end of the inner wire is fixed or clamped in place to
handle grip 32. The rear end of the conduit in the second Bowden
cable is fixed or clamped in place to an upper portion of one
handle tube 28 adjacent the place where the rear end of the inner
wire of the second Bowden cable attaches to handle grip 32. The
front end of the conduit in the second Bowden cable is clamped or
fixed to front transmission 60 to rock front transmission 60
forwardly during upward motion of handle grip 32 in the direction
of arrow B. In this "live conduit" setup, the upward motion of
handle grip 32 in the direction of arrow B deforms the shape of the
clamped inner wire of the second Bowden cable. This deformation in
the shape of the inner wire causes the "live" conduit of the second
Bowden cable to slide forwardly over the inner wire to push against
front transmission 60.sub.f to rock front transmission 60.sub.f
forwardly. Only one Bowden cable applies force to only one
transmission at any given time with the other Bowden cable not
applying force to the other transmission so that only one
transmission at a time is activated.
Mower 2 equipped with traction drive system 38 of this disclosure
has powered operation of rear transmission 60.sub.r to propel mower
2 forwardly in a variable speed manner as handle grip 32 is gripped
by the user and the user walks forwardly, thereby sliding handle
grip 32 downwardly on handle 26 in an amount proportional to the
walking pace of the user. However, when trying to pull mower 2 back
during a trimming operation or when trying to mow a small patch of
grass in reverse, the user no longer has to use manual force to
manhandle mower 2 in the reverse direction. Instead, the user
merely maintains his or her grip on cross bar 36 of handle grip 32
and walks rearwardly at any desired pace. This will slide handle
grip 32 upwardly on handle 26 to initiate powered operation of
front transmission 60 to propel mower 2 rearwardly at a variable
ground speed commensurate to the walking pace of the user. Thus,
the task of operating mower 2 is greatly eased since mower 2 is
self-propelled both in forward and reverse while maintaining the
functionality of the Personal Pace.RTM. control system of The Toro
Company that had previously been used only on mowers that were
self-propelled in forward only.
The advantages of a mower that is self-propelled in both forward
and reverse is achieved in a cost-effective manner by using
mechanical, gear drive transmissions that are both durable and
inexpensive in comparison to using hydraulic motor/pump
combinations or electric motor/drive combinations. Moreover, since
transmissions 60 used to drive front and rear wheels 8, 10 are
different from one another and are mounted on separate front and
rear axles, this allows rear transmission 60.sub.r to have a split
axle/differential action configuration while front transmission
60.sub.f has a solid axle/non-differential action configuration.
The manner of driving front and rear wheels 8, 10 using the same
size drive gears 62 on the ends of the axles of the front and rear
transmissions and the same size driven gears 66 on the wheels, but
simply reversing which sides of driven gears 66 are engaged by
drive gears 62, leads to increased part commonality and thus
reduced cost. This allows a powered, reversible mower to be
manufactured and sold at a reasonable cost.
Referring now to FIGS. 4 and 5, a second embodiment of a mower
according to this disclosure is illustrated generally as 2'. The
same reference numerals used in FIGS. 1-3 to refer to components
will be used in FIGS. 4 and 5 to refer to the same or corresponding
components with a prime designation being used to refer to those
components in the second embodiment, e.g. mower 2' in FIGS. 4 and 5
as opposed to mower 2 in FIGS. 1-3.
Referring now to FIG. 4, in mower 2' front transmission 60.sub.f'
and its axle 64' have been relocated from the front to the back of
mower 2' so that only rear wheels 10' are reversibly driven by the
dual transmissions 60.sub.f' and 60.sub.r' with such transmissions
and their axles being disposed on opposite sides of the axis of
rotation of rear wheels 10'. In this embodiment, front wheels 8'
are present but unpowered with only rear wheels 10' serving to
self-propel mower 2'. As in the first embodiment concerning mower
2, only one transmission 60' (driven by belt 70' and having a drive
gear 62' engaged with driven gear 66') is active at any given time
while the other transmission 60' (driven by another belt 70' and
also having a drive gear 62' engaged with driven gear 66') remains
inactive. Propelling rear wheels 10' in opposite directions may
yield better traction than using front wheels 8' to drive mower 2'
in the direction that is opposite to the direction that rear wheels
10' drive mower 2'. This is due to the fact that more of the weight
of a mower like mower 2, 2' is over rear wheels 10' as compared to
front wheels 8'. In addition, the filling of a grass clipping
collection bag at the rear of mower 2' with grass clippings during
a mowing operation only accentuates this rearward weight
distribution.
In mower 2' as shown in FIG. 4, whichever transmission 60' is used
to produce forward motion of mower 2' is preferably one having a
split axle/differential feature as described earlier with respect
to rear transmission 60.sub.r in mower 2. The other transmission
60' that is used to produce reverse motion of mower 2' could also
be one having a split axle/differential feature since both
transmissions are now being used to power rear wheels 10'. However,
since the times at which reverse motion is needed and the distances
over which mower 2' would travel in reverse are much more limited
than what is required for forward motion, whichever transmission
60' propels the mower in reverse could remain a transmission having
a solid axle without any differential ability.
In addition to the use of both transmissions 60' to drive rear
wheels 10', a simplified Bowden cable coupling setup is used in
mower 2' as shown in FIG. 5. In mower 2', pivotal tab 74' now has a
second opening 76 that is disposed on an opposite side of a
horizontal axis of rotation, illustrated as x in FIG. 5, of a pivot
rod 78 compared to the location of first opening 72' in tab 74'. As
taught in more detail in Stalpes, tab 74' is rigidly attached to
rod 78 to pivot by virtue of the pivoting motion of rod 78 caused
by journaling the ends of rod 78 in the mower handle tubes 28'
while a middle U-shaped portion 79 of rod 78 is captured within a
channel 80 in cross member 46' of slidable handle grip 32'. Again,
rod 78 and its interaction with cross member 46' are detailed more
fully in the Stalpes patent which has been incorporated by
reference herein.
When the user slides handle grip 32' downwardly on handle tubes
28', the portion of tab 74' having opening 72' is pivoted
rearwardly as described in connection with the operation of mower
2. This pulls rearwardly on the "live cable" setup of the first
Bowden cable that is connected to whichever transmission 60' is
arranged to drive mower 2' forwardly to actuate the forward drive
transmission 60'. Whichever transmission 60' is arranged to drive
mower 2' in reverse is now connected by a "live cable" setup of the
second Bowden cable to the newly added second opening 76 in tab
74'. Thus, when the user pulls handle grip 32' upwardly on handle
tubes 28' as he or she walks in reverse, the portion of tab 74'
having opening 76 is now pivoted rearwardly to actuate the reverse
drive transmission 60'. Since both transmissions 60' are now at the
rear of mower 2', the length of the second Bowden cable run is
shortened compared to the length required in mower 2, and a "live
cable" rather than a "live conduit" setup of the Bowden cable is
used. This simplifies the routing and arrangement of the Bowden
cables. However, the operation of mower 2' is the same as mower 2,
namely pushing handle grip 32' downwardly as the user walks
forwardly powers mower 2' in a forward direction at a speed
commensurate to the user's walking pace while pulling handle grip
32' upwardly as the user walks rearwardly powers mower 2' in a
rearward direction at a speed commensurate to the user's walking
pace.
Referring still further to FIG. 5, the use of the double headed tab
74' as described above to activate both transmission 60.sub.f' and
60.sub.r' in mower 2' permits a simplified return to neutral system
40'. All that is required now is the use of one or more torsion
springs 82, preferably two such springs 82, surrounding the ends of
rod 78 that lie along and define the rotational axis x of rod 78
with such springs being anchored at one end on rod 78 and at the
other end on a portion of the adjacent handle tube 28'. When handle
grip 32' is located in its centered, neutral, drive disengaging
position, torsion springs 82 are in their unstressed state such
that handle grip 32' is retained in neutral. As rod 78 is rotated
about axis x in either one direction or the other due to motion of
handle grip 32' relative to handle tubes 28', torsion springs 82
get coiled up or twisted in one direction or the other to resist
the motion of handle grip 32' out of neutral. When the user
subsequently releases handle grip 32', the biasing force built up
in the coiled torsion springs 82 is now free to act on handle grip
32' to move it back to neutral.
The return to neutral system 40' as shown in FIG. 5 is simpler and
thus less costly than system 40 shown in FIGS. 1-3 and takes up
less space on mower 2'. Thus, the cable coupling setup and return
to neutral system 40' shown in FIG. 5 could be used with mower 2
shown in FIGS. 1-3 if so desired.
While traction drive systems are shown in FIGS. 1-5 as utilizing
discrete forward and reverse transmissions, such a construction is
exemplary only as other traction drive systems are contemplated.
For example, FIG. 6 illustrate a power equipment unit (e.g.,
self-propelled, walk power mower 300) that utilizes a traction
drive system having a single, variable speed, bidirectional
transmission 360 carried by the deck that alternatively powers one
or more drive wheels (e.g., two rear wheels 310) to selectively
propel the deck over the ground in both forward and reverse
directions. While shown as being used to power the rear wheels 310,
the mower 300 could, in addition or alternatively, include a
bidirectional transmission (see broken line rendering of front
transmission 360 in FIG. 6) powering the two front wheels 308. In
still other embodiments, only one of the front and rear
transmissions may be bidirectional, while the other transmission
provides driving power in only a single (e.g., forward) direction.
Other aspects of the mower 300 may be similar to the mower 2 (or
2') already described herein (e.g., the mower 300 may include the
deck 4, engine 12 (see FIG. 1), blade 16, and handle (not shown,
but see handles described elsewhere herein). Accordingly, further
description of these features of the mower 300 is not provided
herein.
Utilizing a power equipment unit incorporating a singular,
bidirectional transmission 360 may provide various benefits over
dual transmission configurations including, for example, reduced
cost and weight. Moreover, a single transmission may also benefit
from a comparatively simplified control system. For example, cables
(e.g., such as the Bowden cables described above connecting the
handle grip 32/32' to the transmissions) may require connection to
only a single transmission, thereby simplifying cable
routing/adjustment.
FIG. 7A diagrammatically represents a forward/reverse transmission
360 in accordance with one embodiment of this disclosure. While
illustrated with some specificity, the transmission 360 illustrated
in FIG. 7A is exemplary only as other bidirectional transmissions
are certainly contemplated within the scope of this disclosure.
The transmission 360 may be carried by the deck 4 and may include
an input sheave 362 powered by a belt 70 (belt is not illustrated
in FIG. 6 as it is beneath cover 71, but see FIG. 3) connected to
the drive shaft (see 14 in FIG. 3). The sheave 362 is fixed to a
journaled shaft 364 having a bevel gear 366 such that, when the
sheave 362 rotates, the bevel gear 366 rotates in the same
direction.
The bevel gear 366 meshes with first (forward) and second (reverse)
bevel gears 368, 370, which are each journaled for rotation about
an axis 305 perpendicular to an axis of the shaft 364. As a result,
when the input sheave 362 rotates, the first and second bevel gears
368, 370 also rotate about their axis 305, albeit in opposite
directions.
A cone gear 372 may be located between the first and second bevel
gears 368, 370. The cone gear may be selectively translatable
between: contact with the first bevel gear 368; and contact with
the second bevel gear 370. The cone gear 372 may include friction
surfaces 374 on each side, the friction surfaces adapted to
alternatively engage associated friction surfaces 376 of the first
and second bevel gears. More specifically, when the cone gear 372
is displaced to the right in FIG. 7A such that its right-side
friction surfaces 374 engage the friction surfaces 376 of the first
bevel gear 368, the cone gear will rotate in a first direction
ultimately corresponding to propulsion of the mower in the forward
direction. Similarly, displacement of the cone gear to the left in
FIG. 7A such that its left-side friction surfaces 374 engage the
friction surfaces 376 of the second bevel gear 370 will cause the
cone gear to rotate in a second opposite direction ultimately
corresponding to propulsion of the mower in the opposite, reverse
direction.
The cone gear 372 includes gear teeth that mesh with an axle gear
378 operatively connected to the drive wheel axle 364. As already
described above, the axle 364 may include a differential 380
(diagrammatically illustrated) that allows each drive wheel to
rotate independent of the other, i.e., during turns. While shown as
incorporating the differential 380, other embodiments may use a
solid axle without departing from the scope of this disclosure.
The cone gear 373 may be connected, via Bowden cables 382, 384 to
the mower's control system. For example, with the control system
shown in FIG. 5, the cable 382 may be connected between the cone
gear 372 and the opening 72', while the cable 384 may be connected
between the cone gear and the opening 76. As a result, when the
operator moves the handle 36' (see FIG. 5) downwardly, the tab 74'
may pivot such that the opening 72' moves rearwardly, displacing
the cable 382 and causing the cone gear 372 to slide to the right
in FIG. 7A. As the friction surfaces 374 of the cone gear engage
the friction surfaces 376 of the first bevel gear 368, the cone
gear will rotate in the first direction, causing the mower to be
propelled in the forward direction.
Similarly, when the operator moves the handle 36' upwardly in FIG.
5, the tab 74' may pivot such that the opening 76 moves rearwardly,
displacing the cable 384 and causing the cone gear 372 to slide to
the left in FIG. 7A. As the friction surfaces 374 of the cone gear
engage the friction surfaces 376 of the second bevel gear 370, the
cone gear will rotate in the second direction, causing the mower to
be propelled in the reverse direction.
Engagement of the cone gear 372 with either of the bevel gears 368,
370 may be proportional to the movement of the handle 36'.
Accordingly, the speed of mower propulsion may be associated with
the degree of movement of the handle 36'. That is to say, the speed
of the mower 300 (in both forward and reverse directions) may be
dependent upon how much force the operator applies to the handle
36'.
The forward/reverse transmission 360 shown in FIG. 7A may be
powered, via belt 70, by the mower's prime mover 12 (see, e.g.,
FIG. 1), the latter of which may be an internal combustion engine,
an electric motor, or another power source. That is to say, the
transmission 360 may be powered by the same power source used to
rotate the cutting member 16 (see, e.g., FIG. 6).
However, such a configuration is not limiting. For example, FIG. 7B
illustrates a bidirectional transmission 1360 that is similar in
many respects to the transmission 360 described above. Instead of
receiving power from the prime mover 12, however, the transmission
1360 includes an independent propulsion motor 1362 connected to or
integral with the transmission to provide power to the same. For
instance, the motor 1362 may be an electric motor that is powered
by an onboard battery system 1364 that may also provide power to
the prime mover 12 (assuming the latter is configured as an
electric motor). While the actual construction of the battery
system 1364 may vary, it may in some embodiments include one or
more lithium-based battery cells as is known in the art.
Alternatively, the motor 1362 and prime mover 12 could be powered
by separate and independent battery systems. Still further, one or
both of the motor 1362 and prime mover 12 could receive AC power
from an external power source.
In yet another potential drive system, the transmission may be
configured as one or more, e.g., two, independent electric motors
1462 directly coupled to the mower drive wheels (e.g., one to each
of the rear wheels 310) as shown in FIG. 7C. As with the motor
1362, the motors 1462 may be powered by a battery system 1364 that
is either dedicated to mower propulsion, or is shared with the
prime mover 12 (not shown in FIG. 7C). Each electric motor 1462 and
1362 may, as is known in the art, be reversible to provide the
desired forward/reverse propulsion.
One benefit of the electric transmissions 1360, 1462 is that no
mechanical interconnection is required between the handle and the
transmission. Instead, a cable or wire harness adapted to carry
electrical signals (or an equivalent wireless protocol) may be used
to provide a command signal to the electric motors based upon a
position of the handle. For example, the handle may include a
position sensor (e.g., linear variable differential transducer) or
similar device that may convert a physical position of the handle
into an appropriate electrical signal that is ultimately provided
to the electric motors. In some embodiments, a microcontroller may
be provided to receive, as inputs, the signals representing the
position of the handle. The microcontroller may then process these
inputs and produce corresponding output commands to the electric
motor(s).
Accordingly, various bidirectional transmission configurations, now
known or later developed, are certainly contemplated within the
scope of this disclosure.
While described above in the context of the handle 36' of FIG. 5,
those of skill in the art will recognize that the handle 36 of FIG.
2 could also be utilized with slight modification with the mower
300. Moreover, control systems other than the handles 36 and 36'
are also contemplated. For example, FIG. 8 illustrates a mower 400
having a handle 426 that incorporates two independently movable
control members, e.g., first and second bails 435 and 436. The
bails 435 and 436 are each movable between a neutral position
(corresponding to a neutral mode of the drive system), and an
engaged position (corresponding to a powered mode of the drive
system). The bails may be connected by cables 382 and 384,
respectively, to the transmission 360 (not shown in FIG. 8, but see
FIG. 7A). As a result, movement of the bail 435 from its neutral
position to its engaged position translates the cone gear 372 to
the right in FIG. 7A, resulting in forward mower propulsion (e.g.,
forward powered mode), while movement of the bail 436 from its
neutral position to its engaged position translates the cone gear
372 to the left in FIG. 7A, resulting in reverse mower propulsion
(e.g., reverse power mode). In one embodiment, the engaged position
of both bails is achieved by pivoting the bail (about the handle)
until it rests against the cross member 430 as indicated in broken
lines in FIG. 8.
The bails 435, 436 may include an interlock that prevents
engagement of one bail unless the other is in a neutral position.
In other embodiments, the diametrically opposing forces applied to
the cone gear 372 by the cables 382 and 384 (see FIG. 7A) may
effectively negate the need for such an interlock as the bail with
the highest operator engagement force will determine the
direction/speed of mower propulsion.
As indicated above, the mower 300 may include the single
forward/reverse transmission 360 (or 1360, 1462) at the rear axle
to effectively provide driving power to the rear wheels 310.
Providing both forward and reverse operation at the rear axle is
beneficial as, for example, the rear wheels typically bear a
substantial portion of the mower weight and further allow for both
forward and reverse propulsion even when the front wheels 308 are
lifted off the ground (e.g., during a turn). However, the
forward/reverse transmission 360 (or 1360, 1462) could
alternatively be located at the front axle in other embodiments.
Still further, the mower 300 could provide a forward/reverse
transmission at both front and rear axles (see, e.g., broken line
transmission 360 in FIG. 6), or a forward/reverse transmission at
one (e.g., rear) axle, and a forward-only transmission at the other
(e.g., front axle). The latter configuration would provide not only
powered forward and reverse propulsion, but also all-wheel drive
when operating in the forward direction.
FIG. 9 illustrates a mower 500 in accordance with another
embodiment of this disclosure. The mower 500 may be similar in many
respects to the mower 2, 2', 300, and 400 already described herein.
However, the mower 500 differs in that the two front wheels 508
each form part of a caster assembly 509 having a caster arm
rotationally connected to the deck so that each front wheel
assembly, and thus, its associated front wheel, is permitted to
caster or rotate about a vertical caster axis 511 relative to the
deck 6. With forward/reverse propulsion provided by the rear wheels
510, castering front wheels 508 may provide the mower 500 with
improved maneuverability by, for example, reducing or even
eliminating the need to lift the front wheels during turns. The
mower 500 may include any one of the handles described elsewhere
herein.
While various traction drive configurations are described and
illustrated in FIGS. 1-9, those of skill in the art will understand
that other embodiments are certainly possible without departing
from the scope of this invention. Moreover, features of the various
embodiments described may be combined/substituted with one another
to produce yet even additional embodiments. Accordingly, the
embodiments described and illustrated herein are exemplary
only.
During reverse mower operation, the force vector applied by the
operator to the mower handle (e.g., which results in an applied
moment to the handle about the handle/deck attachment point) may
reverse. This reversal may ultimately result in a downward force
being applied to the mower handle. In some instances, this downward
force may cause the front of the deck to lift upwardly. As
described below, embodiments of the present disclosure may address
such lifting by utilizing a handle that provides a degree of float
during mower operation.
FIGS. 10A-14 illustrate a walk power mower 200 in accordance with
another embodiment of the present disclosure. With the exceptions
noted below, the mower 200 may be mostly identical to the mower 2
(or 2' or 300) already described herein. For example, the mower 200
may include a cutting deck 204 that may be self-propelled, i.e., it
may include a variable speed traction drive system having one or
more transmission(s) carried by the deck as described herein. The
drive system may be capable of selectively providing driving power
to one or more of the wheels in both a forward and a reverse
direction. Alternatively, the mower 200 may incorporate a
conventional transmission (e.g., rear-wheel drive, front-wheel
drive, or all-wheel drive) that is capable of selectively providing
driving power to one or more of the wheels in only a single (e.g.,
forward) direction. For brevity, aspects of the mower 200 that are
either commonly known in the art, or that are already described
herein above, are not further described below.
As shown in FIGS. 10A-10B, the grass cutting deck 204 is supported
upon the ground 203 by a front wheel (e.g., a pair of
ground-engaging front wheels 208) and a rear wheel (e.g., a pair of
ground-engaging rear wheels 210). Again, the traction drive system
may drive at least one of the front wheels and/or rear wheels
forwardly to propel the mower 200 as it traverses the ground 203 in
a forward direction, while the same or different wheel(s) may
optionally be driven rearwardly to propel the mower in the reverse
direction as already discussed herein. In other embodiments, the
wheels of the mower may be undriven, i.e., the mower may move under
operator push-power only.
The deck 204 may further support a prime mover 212 such as an
electric motor or gasoline-powered engine. The prime mover may
power not only the drive wheels of the mower, but also a cutting
blade 16 (see FIG. 3) operable to rotate within the deck.
A handle 226 extends upwardly and rearwardly from the deck 204 as
shown in FIGS. 10A-10B. As with the handle 26 of the mower 2, the
handle 226 may include a pair of laterally spaced-apart and
parallel handle members or tubes 228 extending upwardly and
rearwardly from the cutting deck. Each handle tube includes an
upper end forming a grip area, e.g., cross member 230 and/or handle
grip 232. Lower ends of each handle tube 228 may be pivotally
attached to the deck 204, e.g., to a rear portion of the deck.
While shown as incorporating two parallel handle tubes, mowers with
handles formed from a single handle member or tube are also
contemplated.
The handle 226 of the exemplary mower 200 may include a U-shaped
handle grip 232 having a pair of laterally spaced legs 234
connected by an upper cross bar 236 at or near the upper ends of
the handle members. As with the mower 2, legs 234 of the handle
grip 232 may be telescopically attached near the upper ends of the
handle tubes 228 for sliding movement (translation) relative
thereto. Thus, handle grip 232, like the grip 32 described above,
forms a control system or member slidable downwardly (and
optionally upwardly) on the handle tubes 228 as the user walks
forwardly (and optionally, rearwardly) while gripping the cross bar
236 with the user's hands. That is to say, the control member of
the handle 226 is operable to engage the variable speed traction
drive system to selectively propel the cutting deck 204 in one or
both of the forward and reverse directions in a manner already
described herein with respect to the mowers 2 and 2'.
Of course, in other embodiments, the handle 226 may include an
alternative control member for interfacing with the traction drive
system to control mower propulsion, or it may completely lack any
such control member/traction drive system (i.e., when configured as
a push-powered mower).
The lower ends of the handle tubes 228 may pivotally attach to the
deck 204 such that the handle 226/handle tubes 228 may pivot about
a horizontal transverse pivot axis 250 (e.g., an axis that is
transverse to a direction of forward or reverse travel of the deck)
as shown in FIG. 11. To accommodate this pivotal connection, the
mower 200 may include left and right upright float plates 252
associated with the left and right handle tubes 228, respectively.
The plates 252 may each define an aperture operable to receive a
fastener (e.g., pin/nut 254) passing through an aligned aperture in
its associated handle tube 228. The pins/nuts 254 thus define the
pivot axis 250 about which the handle (e.g., handle tubes) may
pivot.
Each handle tube 228 may also include a handle latch 256. Each
latch may include a lever 258 that is rotatable (e.g., 90 degrees)
to allow extension and retraction of a latch pin 260. In the
operating position illustrated in FIG. 11, each pin 260 may be
engaged with a slot 264 formed in the associated plate 252. The
slots constrain the handle 226 (handle members 228) not to a
singular position like the notches 262 (described below), but
rather allow the handle 226/tubes 228 to pivot, relative to the
deck 204, between: an upper stop 266a (upper end of the slot 264)
corresponding to the handle being in a first operating orientation
R (see FIG. 14); and a lower stop 266b (lower end of the slot)
corresponding to the handle being in a second operating orientation
B (see also FIG. 14). The upper and lower stops 266a, 266b thus
define an operating range of pivotal motion of the handle (i.e., of
the handle tubes). In one embodiment, the operating range of
pivotal motion is at least about 5 degrees (i.e., about 5 degrees
or more) of rotation about the pivot axis 250. For example, in some
embodiments, a range of about 5-20 degrees, or a range of about
8-12 degrees, is contemplated.
By retracting the latch pins 260, the handle 226/handle members 228
may also be moved from the operating orientations to a third or
storage orientation S shown in broken lines in FIG. 14. In the
storage orientation S, the handle 226/handle tubes 228 is
positioned generally vertically to reduce the footprint of the
mower during non-use. The handle 226 may be latched in the storage
orientation by extending the pins 260 into engagement with
associated notches or openings 262 formed on the plates 252 (see
FIG. 11). As one can appreciate, the storage orientation S is
outside of the operating range of pivotal motion defined by the
slots 264 and stops 266a, 266b. While shown as placing the handle
226/handle members 228 in a generally vertical storage position,
such a configuration is not limiting. For instance, other
embodiments may locate the notches 262 (or, alternatively, provide
an additional set of notches 262) to allow for handle 226/handle
member 228 storage at a different angular orientation. One such
orientation may place notches 262 such that the handle 226/handle
members 228 extend forwardly and generally parallel to the ground
203 (see FIG. 14) when in a storage orientation S'.
As shown in the exploded view of FIG. 12, each plate 252 may
rotatably attached to an upright flange 253 of the mower deck via
its associated pin/nut 254 such that it may rotate about the
transverse pivot axis 250. To rotationally secure each plate 252 in
place relative to its associated flange 253, a fastener 255 and
threaded knob 257 may be provided. The fastener 255 may be inserted
through an aperture 259 in the flange 253 and into one of two (or
more) holes 261a, 261b formed in the bracket 252. By pivoting the
plate until the appropriate hole 261a, 261b aligns with the
aperture 259, the mower may provide varying handle operating
heights to accommodate a broad range of users. Once the fastener
255 is inserted through the desired hole 261a or 261b of each plate
252, the threaded knob 257 may be secured to the fastener 255 to
lock the plate 252 in place.
With reference now to FIGS. 11-14, the mower 200 may also include a
handle float system adapted to bias the handle (e.g., the handle
members) toward the upper stop 266a. In one embodiment, the float
system includes a resilient member, e.g., left and right resilient
members 272, operatively positioned between each lower stop 266b of
the cutting deck and its respective handle member 228. For example,
in the illustrated embodiment, the left and right resilient members
272 may be positioned such that they abut a lower side of the left
and right handle tubes 228, respectively, when the handle is at
rest (when the handle is in the operating orientation R (see FIG.
14) and no user loads are applied to the handle). In some
embodiments, the resilient members 272 may bias the tubes 228
against their respective upper stops 266a. However, in other
embodiments, the resilient members may be configured to bias the
handle members to a location that is at or near (e.g., slightly
short of) the upper stops when the handle is at rest.
The term "resilient member," as used herein, includes most any
device that is able to deform, displace (e.g., displace a contained
fluid), distort, or contract under load, and then spontaneously
return to (or near) its original configuration when the load is
removed. Thus, in addition to the neoprene cylinder configuration
described below, other resilient members, e.g., a pneumatic spring,
a mechanical or fluidic shock absorber, etc., are also contemplated
within the scope of this disclosure.
To secure each resilient member 272 in place, the mower deck 204,
e.g., the plates 252, may each define a seat 274. In the
illustrated embodiment, each seat is formed by a bent tab of its
associated plate 252 (see FIG. 12). The seat 274 may define an
aperture adapted to receive an integral threaded stud 276 of the
member 272 as shown in FIGS. 12 and 13. The stud 276 may pass
through the aperture in the seat 274 and be secured relative to the
plate 252 with a nut 278.
Each member may be constructed of a resilient elastomeric material.
For example, while not wishing to be bound to any specific
configuration, each member 272 may be a neoprene disk or cylinder
having a durometer of 60 Shore A. In the illustrated embodiment
(see, e.g., FIG. 13), the cylinder may have a height of about one
inch and a diameter of about 1.25 inches. However, members of other
materials, hardness, size, and geometry are certainly
contemplated.
During operation of the mower 200 over the ground 203, the handle
226 may be used to control forward propulsion at already described
above with reference to the mower 2 and 2'. For example, as shown
in FIG. 14, the user may apply a force 280 that either: displaces
the handle grip 232 downwardly along the handle tubes 228 to engage
the traction drive system; or, where the mower is push-powered,
pushes against the cross member 230 sufficiently to move the mower
forwardly. In the case of the former, as the user walks forwardly
and applies this input force 280 to the handle grip 232, the handle
grip moves from a neutral position (wherein the traction drive
system is inactive), to a first engaged position, causing one of
the transmissions to engage and propel the mower in the forward
direction.
As this user-applied force 280 is offset from the deck 204, it may
also produce a pivoting force on the handle 226/handle tubes 228
(about the axis 250 (see also FIG. 11)) in a clockwise direction
282 as shown in FIG. 14. However, the upper stop 266a of the slot
264 (see also FIG. 11) will effectively limit this pivotal movement
of the handle (relative to the deck 204). As stated above, however,
some minimal pivotal movement in the direction 282 may be
accommodated before contact occurs between the pin 260 and the
upper stop 266a. However, once the hard stop 266a is contacted,
further movement of the handle 226 (relative to the deck) in the
direction 282 may be constrained.
When the user instead applies a pulling input force 284 to the
mower handle 226 (e.g., directly to the handle grip 232) in a
reverse direction, the handle grip 232 may move upwardly along the
handle members from the neutral position to a second engaged
position. In the second engaged position, the traction drive system
may activate for propulsion in the reverse direction. Moreover, as
this reverse motion occurs, the handle 226/handle members 228 may
pivot (about the pivot axis 250) in a counterclockwise direction
286, i.e., toward the lower stop 266b (see FIG. 11) corresponding
to the second operating orientation B of the handle. As this
pivotal movement occurs, each handle tube 228 may compress and
resiliently deform its associated member 272. As a result, the
moment of the handle 226 is reacted, at least initially, by
compression of the members 272, allowing substantial downward
movement of the handle (e.g., cross member 230/hand grip 232) to
occur and be isolated (at least initially) from corresponding
upward movement of the mower's front wheels 208. Of course, once
the members bottom out on the hard stop 266b (see FIG. 11), further
movement of the handle 226 in the direction 286 may begin to
elevate the mower's front wheels 208.
With a mower 200 like that described herein incorporating two
neoprene members 272 as described above, the handle 226 may pivot
about its pivot axis 250 (in the direction 286) about 10 degrees
from its at rest position R (shown in solid lines in FIG. 14) to a
bottom position B before the front wheels 208 would begin to rise.
While varying geometries are possible, one embodiment of the mower
200 may use a handle that is roughly 32 inches long (measured from
a centerline of the cross member 230 to the pivot axis 250). With
this construction, the cross bar 230 may move a linear distance
(e.g., along an arc 288) of approximately 5-10 inches, e.g., 6
inches, as the handle tubes move from the upper stop 266a to the
lower stop 266b (see FIG. 11). Of course, depending on the
stiffness/configuration of the members, the weight and weight
distribution of the mower, and the magnitude of the force 284, the
members may effectively form the lower stops. That is to say, the
members 272 may reach a maximum deflection before the pins 260
contact the lower stops 266b. However, in other embodiments, the
members may continue to compress up and until the lower stops 266b
are contacted by their respective pins 260.
Floating handles such as those described herein may thus allow at
least some degree of downward movement of the handle to occur
without causing associated lifting of the front wheels. As a
result, mowers that utilize a sliding control member to initiate
rearward propulsion (e.g., like the handle 226 described herein)
may permit rearward/downward handle movement without causing front
wheel lifting (at least during typical and expected operation).
This advantage may be especially useful for mowers that incorporate
reverse drive at the front wheel axle. However, even for mowers
that provide no powered reverse operation, floating handles in
accordance with embodiments of the present disclosure may still
assist in keeping the front wheels in contact with the ground
during reverse pulling of the mower.
While described herein in the context of a four-wheel mower, such a
configuration is exemplary only. For instance, it is contemplated
that embodiments of the present disclosure may find application to
mowers having tri-wheel configurations (e.g., having only a single
front wheel and/or a single rear wheel), as well as to most any
other multi-wheel/multi-axle configuration. Yet further, mowers
using ground-engaging members other than wheels (e.g., a rear
roller) are also possible. Still further, embodiments of the
present disclosure may find application to mowers entirely lacking
physical ground-engaging members. For example, hover mowers, which
float above the ground on a cushion of air generated by the mower,
may benefit from the concepts (e.g., the biased handle) described
herein. Those of skill in the art will further realize that
embodiments of the present disclosure may also find application to
walk-behind power equipment other than lawn mowers having a
ground-traversing tool housing other than a cutting deck including,
for example, aerators, wheeled debris blowers, cultivators, and the
like.
Various modifications will be apparent to those skilled in the art.
Thus, the scope of this invention is not to be limited to the
details of the various embodiments described herein, but shall be
limited only by the appended claims, and equivalents thereof.
* * * * *